1. Field of the Invention
The present invention generally relates to aluminum bearing metal. It particularly relates to an aluminum bearing metal having improved strength at a high temperature and improved resistance to seizure and which is increased in fatigue strength.
2. Background Art
A conventional object in the field of metallurgy has been intended to improve aluminum bearing metal in its strength at a high temperature, in seizure-resistance, in fatigue strength, and so on, as disclosed, for example, in Japanese Patent Unexamined Publication Nos. 87917/78 and 35744/81.
The aluminum bearing metal disclosed in Japanese Patent Publication No. 12131/77 consists of, by weight percentage, 3-40% of Sn; 0.1-5% of Pb; 0.1-3% exclusive of Sb; 0.2-2% of Cu; and the remaining parts of Al. Further, if necessary, 0.2-3% of any one of Ni, Mn, and Si is added to the above-mentioned components.
The aluminum bearing metal disclosed in Japanese Patent Publication No. 14866/83 consists of, by weight percentage, 3.5-35% of Sn; 0.1-1% of Cr; 1-10% of Si; 1-10% of one or more of Mn, Sb, Ti, Ni, Fe, Zr, Mo, and Co, the contents being not larger than 10% in total; and the remaining parts of Al. Further, if necessary, 3.0% by weight or less of Cu and/or Mg is added to the above-mentioned components. Furthermore, 9.0% by weight or less of one or more of Pb, Bi, and In are added to the above-mentioned components in place of or together with the above-mentioned fraction of Cu and/or Mg.
The aluminum bearing metal disclosed in Japanese Patent Publication No. 21447/77 consists of, by weight percentage 3.5-4.5% of Sn; 3.5-4.5% of Si; 0.7-1.7% of Cu; and the remaining parts of Al. The Al contains ordinary impurities such as 0.5% or less of Fe, 0.2% or less of Mn, 0.2% or less of Mg, 0.05% or less of each of B, Cd, Zn, and Pb, etc.
The aluminum bearing metal disclosed in Japanese Patent Unexamined Publication No. 35744/81 consists of, by weight percentage, 3-40% of Sn; 0.1-9% of Pb; 0.1-3% exclusive of Sb; 3.0-10% in total of one or more of Si, Ni, Mn, Ti, Fe, Zr, Mo, Co, V, and Nb; and the remaining parts of Al. Further, if necessary, 0.1-3.0% by weight of Cu and/or Mg is added to the above-mentioned components.
Each of the known aluminum bearing metal as described above has properties superior to those of other conventional ones. Recently, however, materials for bearings have been used under the conditions of higher loads and higher temperatures as internal combustion engines are required to be miniaturized and to have a high power output. Under these demanding conditions as described above, the conventional materials for bearings have experienced difficulties such as fatigue failure, abnormal wear, seizure, and so on.